Figure 7.

Cerebellar neurons labeled by retrograde transneuronal transport of rabies 4 d after an injection of the virus into the arm area of M1. Top, Infected Purkinje cells seen on a transverse section through the lateral cerebellum. Scale bar, 500 μm. Middle, Enlarged view of the infected cells enclosed by the box at the top. Scale bar, 50 μm. M, Molecular layer; P, Purkinje cell layer; G, granule cell layer. Bottom, Infected second- and third-order neurons in the anterior interpositus nucleus 4 d after an injection of rabies into M1. The 4 d survival time is long enough to allow labeling of third-order neurons. The small labeled neurons (arrows) are typical of third-order, local circuit interneurons that were first seen in the cerebellar nuclei 4 d after cortical injections of rabies. Scale bar, 50 μm.